Most sounds in Quertílian are read as expected. Here are the exceptions and peculiarities.
Vowels
all vowels are monophtongal, full and clear as in Spanish or Italian, no Vowel Shift happened
vowels with accents are long vowels, they are pronounced twice as long
two vowels form a hiatus, if none of them is i or u
hiatus with i or u is marked with a apostrophe between the vowels
A special feature of Quertílian is that it differentiates between hiatus and a diphthogs formed from the same vowels. For example, admié (die) is different from admi'é (suffer). Hiatus and diphthongs of two identical vowels (aa, i'i, ii etc.) also exist.
Special cases are:
iu is a rising diphthong [ju]
ui is a falling diphthong [uj]
ii is a rising diphthong [ji]
uu is a rising diphthong [wu]
Remember the apostrophe is only used to mark hiatus with an i or u. The frequent combination ao, for example, is always a hiatus. Moreover, the apostrophe does not mark a glottal stop.
Combinations of more vowels are to be pronounced accordingly: For example, in aio [ajo]and ioa [joa] the i is a semivowel and the combinations are bisyllabic, but in i'oa it is a full vowel [ioa] and the combination is trisyllabic.
Consonants
Simple consonants
c is not used
g is a hard g as in German
h is pronounced if standalone, it is also part of digraphs
j is not used apart from foreign words
k is not used apart from foreign words
q is the voiceless uvular plosive, allophonic with the [k] sound
r is tapped
s is voiceless and z is its voiced counterpart
v is not used apart from a few old words (Ris ivoli'il)
w is the [v] sound - voiced labiodental fricative, instead when it is preceded or followed by a labial consonant [m, b] or in the digraph wh
x is pronounced [ks]
y is not used
Digraphs
h in a digraph usually denotes aspiration. Exceptions are
lh is pronounced as a soft aspirated l [λ] (compare Islandish ľ)
qh is pronounced as aspirated [k]
nh is pronounced with as aspirated uvular nasal
rh is rolled [r]
sh is pronounced [sx]
th is pronounced [tx]
wh is an aspirated bilabial [w]
Other special consonant combinations:
ng is the uvular nasal (the g is not pronounced)
ngq and ngg are combination of the uvular nasal with q and g (similar to English encore, English)
qu is [kw]
fq is [fk]